INPAPER INTERNATIONAL - A Publication on World Pulp, Paper & Allied Industry

RESULTS & DISCUSSIONS

The pulp and paper industry is considered as one of the most highly pollutive industries. Pulp and paper production processes utilize large quantities of water and discharge nearly the same volume as wastewater containing various amounts of water-conveyed pollutants. The production of pulp and paper has been known to generate solid, liquid and gaseous wastes. By far, wastewater and sludge are the two most pressing environmental problems confronting the industry (DBP, 1999).

Wastewater Treatment Processes

The survey showed that the 22 pulp and paper mills have facilities to treat their wastewater before final disposal.

Table 1 : Main Grades Produced by the Pulp and Paper Mills and Their Raw Material Requirements
Mill Type/Mill	Raw Material Requirement	Main Grade

1. Non-integrated pulp mill
PM1	Abaca	Abaca-pulp
PM2	Abaca	Abaca-pulp

2. Non-integrated paper mill
A	Imported unbleached kraft pulp, imported and locally sourced waste paper	Corrugated material, sack paper, kraft/ wrapping paper
B	Imported and locally sourced waste paper	Newsprint, printing and writing, tissue
C	Imported bleached kraft pulp, imported and locally sourced waste paper	printing and writing, tissue
D	Imported and locally sourced waste paper	printing and writing
E	Imported and locally sourced waste paper	Packaging paper/ board
F	Imported bleached kraft pulp, imported and locally sourced waste paper	printing and writing, Packaging paper/ board
G	Imported semi-bleached pulp, bleached kraft pulp, imported and locally sourced waste paper	Tissue
H	Imported and locally sourced waste paper	Corrugated material (linerboard/fluting)
I	Imported and locally sourced waste paper	printing and writing
J	Imported and locally sourced waste paper	Cartonboard
K	Imported and locally sourced waste paper	Packaging paper/ board
L	Mechanical pulp, semi-chemical pulp, imported and locally sourced waste paper	Newsprint, printing and writing, carton board, kraft/ wrapping paper
M	Bleached kraft pulp, imported and locally sourced waste paper	Printing and writing
N	Imported and locally sourced waste paper	Printing and writing
O	Unbleached kraft pulp, imported and locally sourced waste paper	Newsprint, printing and writing, sanitary tissues
P	Imported and locally sourced waste paper	Printing and writing
Q	Imported bleached kraft pulp, unbleached kraft pulp, semi-chemical pulp, sulfite pulp, imported and locally sourced waste paper	Printing and writing paper
R	Imported bleached kraft pulp, unbleached kraft pulp, imported and locally sourced waste paper	Newsprint, printing and writing, kraft/ wrapping
S	Imported wood pulp, imported and locally sourced waste paper	Tissue, feminine napkins, disposable diapers

3. Integrated pulp and paper mill
PP1	Mechanical pulp, bleached kraft pulp, unbleached kraft pulp, imported and locally sourced waste paper	Wood pulp, news print, packaging paper/board

Current treatment practices follow the conventional primary and secondary treatment prior to discharge of process wastewater. Primary treatment involves gravity settling to remove settleable solids from the wastewater. The solids consist of lost fiber, bark, and other undissolved organic materials that are part of the pulp and papermaking processes (Amoth, et.al., 1993). A primary clarifier or gravity settling ponds is used to purify the effluents. The sludge removed from the clarifiers are mechanically dewatered and thickened prior to its ultimate disposal in a dedicated landfill or by incineration.

Secondary treatment removes dissolved and residual particulate organic materials using some form of biological treatment. This is accomplished by bacteria and other common microorganisms that convert organic material into carbon dioxide and water. In this type of treatment, an aerated lagoon or activated sludge, anaerobic systems and trickling filters are usually used. Sludge is also generated as a by-product of the treatment process. The amount of BOD5 and TSS produced range from 50 to 95%.

Among the companies that responded, six (6) had settling ponds for their primary treatment operations. Three paper mills subject their wastewater to a screening process prior to secondary treatment process to remove large solid pollutants that might interfere with subsequent treatment processes. Wastewater treatment by dissolved air flotaton (DAF) was used by 11 paper mills which has been reported to be capable of removing 90% of suspended solids present in raw wastewater. One paper mill cited the use of ALGAS Filter which could improve the quality of the final effluent and eliminate fiber cake floating problems in both the existing primary and secondary clarifiers.

Thirteen of the companies surveyed subjected their wastewater to secondary treatment processes to further reduce the BOD loading of their effluents. Nine out of the 19 non-integrated paper mills or 47% of the total paper mills surveyed use the activated sludge process to reduce BOD loading through application of nutrients in the form of ammonia and phosphorus. One paper mill installed a trickling filter for the biological treatment of wastewater discharges from its three paper machines. Four companies cited the use of aerated stabilization basins to treat mill effluents. These paper mills utilized local and imported wastepaper and performed deinking process as a form of pulp treatment.

Table 2: Wastewater Treatment Technologies Adopted by Pulp and Paper Mills
MILL TYPE	MILL	WASTEWATER TREATMENT
MILL TYPE	MILL	Primary	Secondary	Sludge Handling

1. Non-integrated pulp mill
	PM1	Screening	Aerobic system
	PM2	Aerated lagoon	Activated Sludge Process (ASP)

2. Non-integrated paper mills
	A	Clarifier/settling pond	ASP	Sludge dewatering and thickening
	B		Aerated stabilization
	C	Internal flotation save-all and clarifier	ASP	Belt press, thickener
	D	Primary clarifier/ settling pond	ASP	Sludge press
	E	Dissolved Air Flotation (DAF)	Trickling filter
	F	Flotation cell		Dewatering and thickening
	G	Settling pond		Dewatering and thickening
	H	DAF	Aerated stabilization
	I	Microfilters and DAF	Aeration and ASP
	J	DAF		Dewatering and thickening
	K	Flotation
	L	Primary clarifier	ASP	Rotary Screen Thickener and belt press
	M	DAF, primary clarifier		Thickener and sludge press
	N		ASP and Aerated stabilization
	O	Settling process and flotation process	Aerated stabilization	Sludge dewatering and thickening
	P	Settling process and flotation process	ASP	Sludge thickening and dewatering before final disposal
	Q	ALGAS	ASP and Trickling filters	Flotation
	R	Sedimentation, Primary Clarifier, Screening	Aerated stabilization	Belt press and thickening
	S	Primary and Secondary clarifier	ASP	Sludge dewatering and thickening

3. Integrated Pulp and Paper Mill
	PP1	DAF-Chemical Treatment	Aerated stabilization	Sludge dewatering and thickening

In general, the results of the study showed that 100% wastepaper based firms employed the activated sludge process (ASP) and aerated stabilization basins as secondary treatment processes.

The pulp mills surveyed also subjected their effluents to primary and secondary treatment processes through screening, aerated lagoons, ASP and anaerobic treatment systems. The only integrated pulp and paper mill surveyed installed a DAF capable of recovering pulp and clarified wastewater (MAP, 1994).

Sludge dewatering and thickening are carried out in all pulp and paper mills surveyed. These treatment processes used a rotary screen thickener, belt press and sludge press. The treated sludge was disposed in a dedicated landfill, incinerated or recycled. Table 2 summarizes the wastewater treatment technologies adopted by the pulp and paper mills including sludge handling and treatment. The surface waters affected by pulp and paper mills are shown in Table 3. The rivers affected by the operation of the surveyed pulp and paper mills included Agus River, San Cristobal River, Labangan River, Marikina River, Tullajan-Tenejeros River, Meycauyan River, San Isidro River and Bislig River. Based on the Revised Water Usage and Classification/Water Quality Criteria of DAO 35, Series of 1990, all the surface waters receiving the discharge of the pulp and paper mills surveyed are classified as "Class C" water. Under this classification, these surface waters are used for the propagation and growth of fish and other aquatic organisms, for recreational purposes (boating, etc.) and for industrial water supply. Henceforth, wastewater treatment facilities of the pulp and paper mills surveyed must be able to meet the standards for "Class C" waters required by the law.

Table 3: Surface Waters Affected by the Pulp and Paper Mills
Mill Type/Mill	Surface Water Receiving the Discharge	Classification (DAO 34, Series 1990)
A	A	A
1. Non-integrated pulp mill
PM 1	Agus River, Lanao del Norte	C
PM2	San Cristobal River, Calamba, Laguna	C
2. Non Integrated paper mills
A	Labangan River, Bulacan	C
B	Marikina River Marikina	C
C	Baesa Creek, Quezon City	C
D	Baesa Creek, Quezon City	C
E	Baesa Creek, Quezon City	C
F	Tullajan-Tenejeros River, Valenzuela, MMla	C
G	Creek, Cavite	C
H	None	-
I	River, Cavite	C
J	Creek, Cavite	C
K	Meycauayan RIver, Bulacan	C
L	Marikina River, Marikina	C
M	River	C
N	-	-
O	Creek, San Pedro, Laguna	C
P	Tullajan-Tenejeros River, Valenzuela, MMla	C
Q	None, Cabuyao, Laguna	C
R	Laguna Lake	C
S	San Isidro River, San Pedro, Laguna	C
3. Integrated Pulp & Paper Mill
PP1	Bislig River, Surigao del Sur	C

Table 4: Air Emission Technology
Mill Type/Mill	Location	Air Emission Control Technology
A	A	A
1. Non-integrated pulp mill
PM 1	Lanao del Norte	Installed air pollution abatement facilities
PM2	Canlubang, Laguna	Regular bunker fuel check
2. Non Integrated paper mills
A	Calumpit, Bulacan	Operational Control
B	Pasig City	Regular boiler check
C	Quezon City	Boiler has pollution control device
D	Quezon City	Shifting to low sulfur content bunker fuel oil
E	Quezon City	-
F	Valenzuela, Metro Manila	Not clear
G	Cavite	Cyclone filter
H	Cavite	Regular bunker fuel check
I	Cavite	The bunker is equipped with atomizing burner to completely burn fuel, thus no emission problem
J	Cavite	Preventive maintenance of boiler (atomizing burner)
K	-	-
L	Marikina	Mill is equipped with air pollution abatement facilities
M	-	Dust collectors
N	Cavite	Use additives
O	San Pedro, Laguna	-
P	Malabon, Metro Manila	Recover flue gas to make into carbon dioxide for use in a number of purposes
Q	-	-
R	San Pedro, Laguna	Scrubbers
S	San Pedro, Laguna	Regular bunker fuel check
3. Integrated Pulp & Paper Mill
PP1	Surigao del Sur	Electrostatic precipitator for recovery boiler, multi cyclones for bark boilers and peabody scrubbers

Table 5: Solid Waste Handling and Disposal
Mill Type/Mill	Location	Solid Waste Disposal
A	A	A
1. Non-integrated pulp mill
PM 1	Lanao del Norte	Landfill
PM2	Canlubang, Laguna	Solid waste recycling (soil fillers and soil conditioners)
2. Non Integrated paper mills
A	Calumpit, Bulacan	Landfilling, composting and burning (in future)
B	Pasig City	Landfill and solid waste recycling
C	Quezon City	Landfill and solid waste recycling
D	Quezon City	Landfill
E	Quezon City	Landfill and solid waste recycling
F	Valenzuela, Metro Manila	Landfill
G	Cavite	Burning
H	Cavite	Landfill
I	Cavite	Landfill
J	Cavite	Landfill and soild waste recycling
K	-	Landfill
L	Marikina	Landfill and solid waste recycling
M	-	Landfill and solid waste recycling
N	Cavite	Landfill and solid waste recycling
O	San Pedro, Laguna	Landfill and solid waste recycling
P	Malabon, Metro Manila	Landfill and solid waste recycling
Q	-	-
R	San Pedro, Laguna	Landfill and solid waste recycling
S	San Pedro, Laguna	Landfill
3. Integrated Pulp & Paper Mill
PP1	Surigao del Sur	Landfill and solid waste recycling

CONCLUSION AND RECOMMENDATION

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	A Publication on World Pulp, Paper & Allied Industry
October-December' 2001


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